Catheters with electrodes are used in a number of medical procedures, such as investigating or operating on a region of the heart. In these procedures the electrodes may be used, for example, to inject known currents (typically for catheter tracking purposes), to measure electropotentials of specific regions of the heart, and/or to ablate the regions. While catheters with a small number of electrodes, or even with a single electrode, may be used for such procedures, certain software algorithms may increase the value of having large number of electrodes on the catheter. Such an arrangement allows a physician using the catheter to select which of one or more of the electrodes may be used, and also to select if the electrodes are to be used simultaneously or not.